fileInput.addEventListener('change', function (event) {
  const file = event.target.files[0];
  if (file) {
      document.getElementById('fileName').textContent = file.name;
      const reader = new FileReader();
      reader.onload = function () {
          const result = reader.result;
          FS.writeFile('/input.els',result,{
              encoding:'utf-8'
          });
          document.getElementById('displaytext').innerText = result;
          alert('上传成功');
      }
      reader.readAsText(file);
  } else {
      document.getElementById('fileName').textContent = '未选择文件';
  }
});